For an economic system to function there must be winners and losers. In order for an ecosystem to function on a continuing basis there must be a constantly evolving and dynamic balance within and between the populations of animals living in it.
This balance allows all species within the system to continue to exist and evolve. Ecosystems can and will go out of balance for a variety of reasons. These reasons can be natural including floods, forest fires and volcanoes. The human causes are numerous but include pollution, habitat destruction, global warming and species introductions. In an unbalanced ecosystem one or more of its’ populations usually experience an abnormally large increase in their numbers. There are many examples of how nature deals with an over abundance of any one or group of organisms.
Looking at an ecosystem in its simplest form where there is only one predator species and one prey species with 100 times the predator’s numbers we can see what happens. Other parameters in this example include; the prey reproduces ten times as much per year than the predator does, the only food for the predator is this one prey species, each year in the winter the predator population is cut in half and the prey population drops by 80%, I know, math.
What happens over time is that an oscillation in the population numbers of both the predator and prey species is set up. Under ideal conditions this oscillation is stable with no over population by either species occurring. Now, we throw in a ringer. The local farm cooperative, on one of their seed crops, accidentally introduces a foreign plant fungus.
This fungus is neither predator nor prey relative to the other two species but it infects a plant that is the prey species’ primary food source. Due to this reduction in food 90% of the breeding prey population dies within two weeks of the end of the breeding season so the predators can only feed off the young prey, which haven’t had a chance to breed. This causes the prey population to “crash” even further. The prey doesn’t become extinct because some animals always seem to find a way to live through any disaster. Once the prey numbers are reduced to functional non-existence the predators start to die off. The lack of prey makes them more susceptible to disease and they even start to cannibalize their own species during the winter. After one annual cycle has been run through both populations are now back to their minimal sustainable levels at the start of a new breeding season. You might say this is just the start of another “boom and bust” cycle of their populations but it’s not. The prey that survived have done so because they fed off a different specie of plant during the winter and are no longer dependent of their original plant food source. This trait will be passed on to their offspring. Is not diversity wonderful? The prey has under gone some changes too. Only those predators who were able to live through lean times by whatever means possible survived and they will pass on that trait to their progeny.
The human race is now faced with an analogous situation as its’ population is growing unchecked on a world level. What will be our fate if our food supply is disrupted or a new predator is introduced? It happened not so long ago. In 1918 the new predator was influenza (flu), the so called the Spanish flu. It was called the Spanish flu only because neutral Spain was publicly reporting civilian deaths during WWI. In reality it had nothing to do with originating in Spain. It killed approximately 19 million people world wide in 18 months and then just as mysteriously as it appeared it left. We tend to think of the flu as only a minor inconvenience but it kills about 36,000 people in America every year. Got your flu shot yet
Think Global – Act Local!